1.  20 20 17 17 14 14 11
A. 8 8
B. 11 11
C. 11 14
D. 8 9
E. 11 8

Answer: Option E

Explanation:

This is a simple subtraction with repetition series. It begins with 20, which is repeated, then 3 is subtracted, resulting in 17, which is repeated, and so on.